Katrina H-Wind Analysis, marginal 3 at landfall

[Huckster]

it normally is 90%, but only if there is high ocean heat content near the land, like Miami, or the Caribbean. At Cuba, Charley was actually 105%

I do not believe NWS in the center of New Orleans recorded cat 3 sustained from Betsy as the highest readings I have seen were 105 m.p.h. gusts, but cat 3 sustained at Grand Isle

Here's a little information from the report on Betsy in the TPC archives...

Winds estimated to be 150 mph
Winds of 70 to 105 mph with gusts of 160 mph at Grand Isle at 5 pm CST on Sep. 9 (landfall took place 5 hours later near Grand Isle)
Winds gusting to over 100 mph at Pilottown at the same time
Winds exceeded 100 mph in New Orleans by 10:20 CST
Winds reached 125 mph at 10:48 pm when the power failed

The eye moved over Houma between midnight and 1 am and produced wind gusts over 130 mph and a pressure of 28.00 inches.
At Thibodaux, the pressure fell to 28.02 inches and winds gusted to .
The storm still maintained 100 mph winds as it passed west of Baton Rouge.

That information can be found here ftp://ftp.nhc.noaa.gov/pub/storm_archiv ... elim08.gif

I have a copy of a report issued by the then Weather Bureau in New Orleans. Here are some peak wind gusts in LA according to that report:

Amite 110
Baldwin 100
Carville 130
Covington 100
Grand Isle 160+
Hammond 115
Melville 90
Monroe 61
Morgan City 128
New Iberia 85
New Orleans:
WB City Office 125 (incomplete record)
Moisant 112
Causeway 105+
Huey Long Bridge 128
New Roads 100
Port Sulphur 166
Pilottown 120+ (Sustained)

For Mississippi...
Bay St. Louis 80
Columbia 67
McComb 63

The lowest pressure measured at both Grand Isle and Houma, which is a good way to the NW of Grand Isle was 28.00 inches and at Thibodaux, even farther inland, 28.02 inches.

Per the report in the newspaper (can't remember if it was the State Times or the Advocate, have to look it up again), winds in and around Baton Rouge reached 100 to 120 mph (gusts no doubt).

[oneness]

science is bunk? You really need to live in the middle ages then when you could just burn the scientists at the stake for presenting evidence that contradicts your incorrect beliefs

There is ZERO chance of Katrina being anything higher than a 3 at landfall

Not at the 1st landfall at Buras Lousiana.

It was a Cat 4.

And if the wind speed doesn't reflect it then the damage does. There is a zero chance of you being right. Accept it.

Because you know, damage IS a factor in determining damage with hurricanes, (ANDREW)

Dude x again says, “t’was cat 4 damage levels!!", at an initial landfall over the delta ... and yet again it has to be reiterated that those damage levels there were ~95% storm surge related, upon extremely flat terrain which barely pokes above sea level during high tide to begin with.

You should check out the non-surge damage in higher coastal areas like north Diamondhead, and Slidell/Stennis Space Center/Picayune, which were in the western and eastern eyewall, respectively. That damage is hardly insignificant. In addition, these damaging effects were felt well inland past the short amount of "extremely flat terrain" that "barely pokes above sea level."

I would estimate that in my part of the the neighborhood (70-100 feet above sea level) that 80-85% of the trees were lost in Katrina.

It has been pointed out numerous times now (and even immediately above your last post), actual measurements put the landfall strength over Slidel as Cat 3 strength as did the official NHC warning advice at the time, if you would like to review it. NHC are extremely unlikely to upgrade the Cat 3 assessment based upon the record of direct measurements in that area. There is little to debate about that. But more to the point, most of Katrina's most powerful WX remained over water, thus the pronounced asymmetry in wind field strength. You are looking at the phenomenal damage a large mature Cat 3 can inflict. You used Slidel as an example of an area above sea level, yet Slidel was hardly well above sea level, look at surge aftermath on satellite following the passage, and most of Slidel was submerged and also smashed by powerful surge. Many homes immediately above this surge line remained structurally intact.

If you want to see what a genuine Cat 4 sustained wind really does to suburbs, look at the recent TC Tracey thread. Anyone who has seen cat 4 winds in person can see that Katrina was no Cat 4 at landfall. Show me an area (above surge line) which exhibits typical straight-line wind damage which looks like this below. The main problem is that people can’t comprehend how much more damaging genuine cat 4 wind actually is. I've seen a lot of wind damage images from Katrina but none of them exhibit the extreme ferocity levels of cat 4. The image shown below was not the exception it was typical of each and every street and in many areas it was even worse.

http://img291.imageshack.us/my.php?imag ... pct9gi.jpg

[Stormcenter]

Thats odd that it was bogus, it would have coincided with the gusts to 215 mph that 175 mph hurricanes should have.

A) Katrina was most likely never 175 mph, per NHC.
B) That wind report was well aloft.
C) 80 feet above and below that report winds were much lower. Pretty hard to get a gust in one very small part of the atmosphere.

So what you are saying the NHC was incorrect and you were concerning the 175mph, hmmmmmm? I would side with the NHC on that but hey as I've said many times before we ALL have our opinions. But the buttom line is unless you were out in
the GOM measuring the winds its all basic speculation on your part and everyone elses on this board. Katrina's destruction unfortunately speaks for itself so whatever her top winds were now are really irrelevant. The damage has been done.

[wxmann_91]

Thats odd that it was bogus, it would have coincided with the gusts to 215 mph that 175 mph hurricanes should have.

A) Katrina was most likely never 175 mph, per NHC.
B) That wind report was well aloft.
C) 80 feet above and below that report winds were much lower. Pretty hard to get a gust in one very small part of the atmosphere.

So what you are saying the NHC was incorrect and you were concerning the 175mph, hmmmmmm? I would side with the NHC on that but hey as I've said many times before we ALL have our opinions. But the buttom line is unless you were out in
the GOM measuring the winds its all basic speculation on your part and everyone elses on this board. Katrina's destruction unfortunately speaks for itself so whatever her top winds were now are really irrelevant. The damage has been done.

Not trying to pick a fight here, but

a) He isn't saying the NHC was incorrect, he is saying that the NHC said itself was incorrect saying that Katrina had 175 mph winds.

b) We are debating intensity here because it is important from a scientific standpoint. Use the past to prepare for the future. If it turns out this was a weak Cat 3, we can better inform the public next time how destructive a Cat 3 can really be by using Katrina and Rita as examples.

[oneness]

b) We are debating intensity here because it is important from a scientific standpoint. Use the past to prepare for the future. If it turns out this was a weak Cat 3, we can better inform the public next time how destructive a Cat 3 can really be by using Katrina and Rita as examples.

Not sure this is going to be possible either wxmann, as the aim is of course to reproduce an accurate perception of the actual threat level within the mind of the hearer, viewer or reader. For example, Charlie was supposed to be a relative ‘pussy-cat’ Cat 2. Not a walk in the park but not a ripping banshee either. But Charlie changed it’s direction and intensity over a short time-frame, so the perception and expectations people had in their mind’s-eye, quickly became out-of-step with dynamic reality.

Another good example was Dennis, which hit south Cuba as a heavy-duty cat 4 but exited Cuba's north coast as an (unexpectedly) far weaker marginal hurricane (if that). It slowly regained strength and looked like it would come ashore as a system even worse than Ivan was, but instead it withered to a much smaller and weaken system in the final hours. So again the public perception lagged well behind the observed actual.

It seems the natural way around this problem is to have real-time data and its accurate graphical depiction, piped directly to the media outlets. However, you’re then presented with the serious problem of spurious data and misleading false transient readings inevitably becoming included real-time (such as a 233 kt gust at FL in Katrina’s case …), which again would lead to confusion, misguided perceptions and perhaps inappropriate action or decisions.

Superficially, it seems that regular, near-real-time data would be the solution to this spurious data. But again you’re presenting an opportunity for confusion and false perception due to wobble watching and related second-guessing.

NHC can’t win that battle of perceptions. The fact remains that these storms are dynamic and can, will and do change their bulk characteristics over relatively short time frames. So no matter what you do there is going to be some level of inaccurate conveyance of the perception the NHC wants to propagate, and some level of misguided secondary-interpretation involved.

Then there’s the acute problem of media outlets which all want to apply their own distinctive graphical presentations and narrative emphasis over the commonly supplied NHC data. Thus the same data can look 'different' depending on how it was presented, and who presented it.

On balance I’d say the current NHC forecasting approach and their data presentation may not be far from ‘ideal’, in terms of providing salient timely warning and conveying the desired and relevant perception to the best ability available technology currently allows.

However, if the NHC also had better real-time data then they could convey a more accurate picture, more often, so the public perception is in better agreement with the currently observed dynamics and trends.

The other suggestion I might add is that it may help if the NHC itself prepared and relayed it's own formal live video warnings and forecasts, to all media within the relevant warning and watch areas, rather than supplying the data and text and leaving it up to media to accurately present, deconstruct or misconstrue.

[f5]

did someone on here suggest Katrina wasn't a CAT 5 at sea?also don't annular hurricanes reach a peak then spin down slowly.unlike rita non annular smaller eye just keeps strengthing?

[HurricaneBill]

I dont think we need subcategories, we just need a media that actually will report the facts to better educate the public as all of the info is contained in the public advisory. The media just never relays it properly

Sorry, I didn't explain it too well.

I meant have the sub-categories reserved for landfalls only.

In other words, based on landfall and impact.

For example:

Category 3 landfalls:

Jeanne could be classified as a strong Category 3.

Ivan could be classified as a severe Category 3.

Katrina could be classified as a catastrophic Category 3.

It could be a kind of compromise.

You could say Katrina made landfall as a marginal Category 3. However, due to her massive storm surge and large wind field of hurricane force winds, Katrina has been classified as a catastrophic Category 3.

[Derek Ortt]

works good in theory, but there would be some in the media who may start giving those classifications during the storm.

The media is the concern I have

[HurricaneBill]

works good in theory, but there would be some in the media who may start giving those classifications during the storm.

The media is the concern I have

Good point, after what happened with Charley.

[Recurve]

I dont think we need subcategories, we just need a media that actually will report the facts to better educate the public as all of the info is contained in the public advisory. The media just never relays it properly

I'd like to avoid blanket condemnation of the faceless "media." If the NHC message isn't getting to the public, maybe they need more trained communicators on staff. Is there a single journalist with a graduate degree at TPC/NHC who works on communication issues? I'll send my resume next time there's an opening.

As far as whose job it is to "educate" the public -- News is real-time. Hurricane education can't be.

Maybe we ought to face that people just don't understand what the media OR the NHC tells them about hurricanes. If nothing but the exact words of the NHC were broadcast and printed, people still wouldn't get it. Those of us who study the history and science of tropical cyclones quickly forget how incomprehensible this stuff is to the average person. People convince themselves that they know -- everybody has his own idea of what Cat 3 damage is or what 90 mph winds will do or how high the surge will get -- as we've certainly seen here.

[jasons2k]

Part of the problem is the overall perception from the general public is that unless it's a Cat. 5, they do not respect the power of a hurricane's strength. I brought this point up in the debates about the NOLA evacuees that stayed; that's exactly why so many people stayed in NOLA. Many people just don't equate a hurricane with death and catastrophic destruction, hence the lack of urgency. If they knew a nuclear blast was going to hit in 72-48 hours, not a soul would have been left in the city.

Even after the major hits we had last year, most people still didn't "get it" until Katrina.

The sad thing is that with this thread being so long, apparently many of the more educated ones still don't.

[jasons2k]

Furthermore, there is only so much the NHC and the media can do. At some point, people need to take some personal responsibility.

Before Rita, Mayor Bill White of Houston said it best: "There isn't going to be some big government agency to tell you exactly what to do and where to go at all times. People will need to use their common sense to survive this event."

[Weatherfreak000]

I agree.




If this really is a true situation, then it should be the NHC's duty to report this investigation to us as it continues.



There is no reason we should be left out of the loop if this is indeed a reality. Public Media is not to blame, NHC had it at 145 therefore they report that. I've never heard a news weatherman say otherwise.

[TSmith274]

As far as Katrina supposedly "not being a cat 4 at landfall" in Buras, La... and people are saying "show me straight-line wind damage", etc, etc...

All I can say, and as clearly as possible... There is nothing left in Buras, la and other adjoining towns. I AM NOT EXAGERRATING! Nothing, nada. Even the watertower was blown down. Everything is flattened. The 1% of structures that are still recognizeable are hollowed out.

Now, does this mean she was a cat 4? Who knows. And, I understand the validity of this argument. I understand that it's nothing more than a scientific discussion. And I respect all that.

But, until media and people get down there to see the damage first hand, the standard by which all hurricane destruction from here to eternity will not be known. Like I said in my post earlier... it defies imagination. I've been down there, walked the neighborhoods, and tried to salvage my things. There is nothing left. It is not hit-or-miss. It is complete and total.

But, as a useful observation, it may be wise to make the categorizing of hurricanes a more complex criteria. Wind damage alone doesn't translate to anything. Hurricanes are much more than wind. Therefore, the category is pretty much meaningless. That's a problem.

[john potter]

f5, Katrina showed classical annular structure on August 28, 15-17 hours before LA landfall; annulars typically hold their intensities longer than more typical systems.

[Scorpion]

A typical Cat 3 storm hitting the same area as Katrina did will not do nearly the amount of damage Katrina did. A weakening Cat 5 hurricane hitting as a 3 is a much more potent storm than a strengtheing 3 from a 2.

[quandary]

works good in theory, but there would be some in the media who may start giving those classifications during the storm.

The media is the concern I have

With regard to an "informative" style of measuring hurricanes, we may as well treat Hurricane Katrina as a Category 4 at landfall. Yes, its winds may have been 120 or 130, and perhaps the Hurricane Center can change this upon reanalysis. However, some people have suggested that calling Katrina a Category 4 would make people complacent next time they were getting hit by a Category 4 or maybe a 3. That what they'd be expecting is not up to what would actually be out there, which is probably wrong. Katrina, after all, was a big time Category 3, much worse than most Category 4 storms to hit the United States with its monster surge and its prolonged winds. Katrina, for damage purposes, caused duress that is equivalent to or exceeds any other Category 4, so I doubt people would be expecting too little next time.

[f5]

before Katrina camille was the benchmark that why folks got killed beacuse they thought if they can survive camille they can surive katrina.setting benchmarks can be very dangerous as we just saw

[TS Zack]

Just thought I would pass this along.

Here our some pictures from St. Bernard Parish. That is maybe less than a mile East of me. WE WERE SO LUCKY unlike poor St. Bernard.

http://www.wwltv.com/cleanup/60.htm

[gpickett00]

dang it, this thread went 3 and a half hours without a response, i thought it was going to disappear.